Taste plays a central role in clinical medicine and is crucial for pediatric patients because the unpleasant taste of drugs thwarts the benefits of even the most powerful drug. For two reasons, pediatric medications are particularly problematic. First, children often cannot or will not swallow pills or tablets (which encapsulates the inherently bitter tasting medications). Second, their enhanced (relative to adults) sensitivity to bitterness leads them to strongly reject bitter liquid medicines. We propose experimental studies applying recent scientific advances in bitter taste biology which have identified compounds that may interfere with bitter perception by taste receptor cells, to determine: (1) the effectiveness of these bitter blockers in children and adults for different model bitter compounds and (2) how age and genetic variation affects the efficacy of the bitter blockers. PUBLIC HEALTH RELEVANCE: Completion of this research project will lead to a better understanding of the how to ameliorate bitter tastes. It addresses a public health priority by 1) supporting efforts aimed at formulating better tasting pediatric medications, thus helping children avoid the serious health consequences from refusing to take medications; and 2) providing a framework and database using appropriate psychophysical testing procedures, model bitter compounds and currently identified bitter blockers, which will facilitate future clinical studies in which specific drugs can be compared and novel bitter blockers can be evaluated.